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The safe handling and storage of radioactive materials require an understanding of the effects of radiolysis on those materials. Radiolysis may result in the production of gases (e.g., corrosives) or pressures that are deleterious to storage containers. A study has been performed to address these concerns as they relate to the radiolysis of residual fluoride compounds in uranium oxides. The interactions of radiation with crystalline solids, based on the bonding characteristics of the crystal, are described to enhance the understanding of radiolytic effects in uranium oxides. Samples of U02F2wH20 and U~08 (with -1.4 wt YO fluorine content) were irradiated in a 'Co source and in spent nuclear fiel (SNF) elements from the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory. Container pressures were monitored &roughout the irradiations, and gas and solid samples were analyzed after the irradiations. The irradiation of U02F2~xH20 produced 02-with G(02)-values ranging from 0.007 to 0.03 molecules 02 produced per 100 eV. Neither F2 nor HF was produced by the irradiations. Chemical analysis of solid samples showed that some of the uranium was reduced from U(W) to U(IV). A saturation damage limit for the U02F2SXH20was demonstrated by using the HFIR SNF elements, and the limit was found to be 7-9°/0(at -108 radlh). It is shown that the covalently bonded oxygen is more susceptible to radiation darnage than is the ionically bonded fluorine. Irradiation of U@8 (with -1.4 wt 'XO fluorine content) resulted in neither gas production nor a pressure increase. These experiments led to the conclusion that U@8 is safe during 10ng-tem'Istorage fiOm overpressurization and the production of corrosives caused by gamma radiolysis of residual fluorides.

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